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The World Health Organisation estimates that traditional medicine still plays a vital role in the lives of 70-80 of the populations of developing countries. Approximately 20 000 tons of medicinal plants are estimated to be traded in South Africa annually, resulting in considerable pressure on the wild populations from which these plants are harvested. In 1997, a study was initiated to assess the extent of trade in medicinal plants on the western boundary of the Kruger National Park, and to determine local perceptions of the availability and values of these plants. This paper presents an inventory of the species traded, including vendors' and traders' perceptions of current availability of species and consumer demand, as well as price/kg. In Mpumalanga, 176 species were identified (71 of the vernacular names encountered in the market place), representing 69 families. In Northern Province, 70 different species were identified (84 of the ver-nacular names recorded in the markets), representing 40 families. Perceptions of availability of a species varied considerably, often within the same markets. Perceptions of demand tended to be more consistent, although these also sometimes varied. Although monitoring markets is an efficient means of assessing the conservation status of medicinal plants, it is important to select appropriate parameters. Markets often differ from one another, and an understanding of local conditions is crucial. For example, in the medicinal markets on the western boundary of the Kruger National Park, price/kg and market perceptions of availability of species were highly variable and would thus not provide a consistent monitoring parameter. Perceptions of demand provide an indication of current and potential pressure on a species, particularly when combined with the monitoring of species traded, and the introduction of substitutes in the market place. The size of plant parts traded could also provide useful monitoring data. It is important to identify the plants utilised locally first hand where possible, due to the variation of vernacular names from one area to another

Gold and uranium tailings ( 'slim es') dams and the adjacent polluted soils in the deep-level mining regions o f South Africa (Carletonville, Klerksdorp and Welkom) were surveyed for the frequency o f occurrence o f naturally colonizing, actively introduced and persisting plant species. Fifty-six tailings dams with a combined area o f 5864 ha. and a similar area o f tailings-polluted soils, were surveyed between July 1996 and March 1997. During the survey, 376 plant species and subspecies were recorded from the dams and adjacent polluted soils, with an additional 8 6 records obtained between 1998 and 2003 (i.e. a total o f 462 taxa: species and infraspecific species). Overall, the most commonly represented families were the Poaceae (107 species and subspecies), Asteraceae (81). Fabaceae (55) and Anacardiaceae (16). with other families represented by just one to 14 species. Only 60 species were common to all three regions, and o f these 24 had been introduced during rehabilitation attempts. Most o f the species found on tailings were persisters or natural colonizers (53-88%, depending on substrate), with the vast majority being indigenous and perennial taxa (76% and 85% respectively), with semi-woody to woody growth forms (6 6 % being resprouters, forbs, shrubs and trees). Less than 4% o f the naturally-colonizing taxa found during the survey had also been introduced by vegetation practitioners. The majority o f introduced plants were alien herbaceous taxa. The number and frequency o f annuals was only high on recently vegetated sites, whereas annuals were rarely present on old-vegetated and never-vegetated dams. This list includes a wide range o f indigenous plant species that may be suitable for phytoremediation o f tailings dams and polluted soils due to their apparent tolerance o f acid mine drainage and salinity.

Citation: Muvengwi, J, AB Davies, F Parrini, and ETF Witkowski. 2018. Geology drives the spatial patterning and structure of termite mounds in an African savanna. Ecosphere 9(3):e02148. 10.1002/ecs2.2148Abstract. Termite mounds perform important roles in savanna ecosystems, generating heterogeneity and influencing ecosystem processes across multiple trophic levels. However, the influence the environment and neighboring termite colonies have on mound spatial patterning and structure is poorly understood, despite the profound implications such dynamics can have on ecosystems. To better understand these drivers, we mapped the spatial distribution and size of active and inactive Macrotermes mounds in eight 1-km 2 plots on contrasting geologies, nutrient-rich granite and nutrient-poor basalt, in a semi-arid Zimbabwean savanna. Although mound density was not significantly different between basalt (5.5 mounds/ha) and granite (6.1 mounds/ha), termite mound structural attributes and spatial distribution patterns varied greatly between geologies. Mound size distributions differed between the geologies and mounds were 2.6 times taller and 3.9 times wider and had 15 times greater lateral surface area on granite. Subsequently, 6% of the total landscape was covered by mounds on granite compared with only 0.4% on basalt. On granite, large mounds exhibited significant over-dispersion at scales below 30 m, signifying density-dependent thinning. Furthermore, small mounds were clustered around large mounds, likely a result of the budding of new colonies comprising fully fledged castes less vulnerable to competition. In contrast, random patterning was evident on comparably homogenous basalt. Our results demonstrate the powerful influence geological substrate has on mound spatial patterning and structure, suggesting that the importance of termite mounds for ecosystem functioning is more pronounced on nutrient-poor granitic substrates than basalts because of the pronounced over-dispersion, which maximizes mound production per unit area, and much larger mound sizes here.

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